Mitochondrial Mutations May Cause Males to Have a Shorter Lifespan

In 2008, an article published in Time stated that 85% of people who lived to be 100 years old were women.  Why does this happen?  A study published this summer in Current Biology provides a possible answer: genetics.  Researchers at Monash University in Melbourne, Australia, have found that mitochondrial differences may cause women to have a longer life expectancy than men.  Mitochondria are a type of organelle found in the cell’s cytoplasm.  The mitochondria in the cytoplasm convert oxygen and sugar into ATP, the cell’s energy source.  The researchers used fruit flies, a model organism, to study aging between males and females.  Fruit flies, like other model organisms, are valuable tools for study because they have short generation times and short lifespans.

[caption id="" align="aligncenter" width="320" caption="Mitochondria and the other organelles of a cell."][/caption]

The results of the study showed that certain genetic mutations found in male mitochondria had an impact on the lifespan of male fruit flies.  However, similar mutations in female fruit flies did not yield a similar effect on lifespan.  The researchers believe that the results from this study could be applied to other animals because all animals contain DNA and females tend to outlive males.  Mitochondria are passed down from generation to generation through maternal inheritance.  This type of inheritance only allows natural selection to act in females.  Therefore, detrimental mitochondrial mutations found in males will continue to propagate over many generations.  The scientists think that thousands of generations of harmful mutations in males have caused males to have shorter lifespans than females.

I found the researchers reasoning on why females live longer than males to be interesting.  The results of this study should encourage the development of new gene therapy techniques to mitigate the harmful mitochondria mutations found in human males.  If this is done, males may be able to live as long as females.  Scientists should also conduct further research on other cellular processes in the body to see if there are other reasons why males tend to have shorter lifespans than females.